Glacier change along West Antarctica's Marie Byrd Land Sector and links to inter-decadal atmosphere-ocean variability
Glacier change along West Antarctica's Marie Byrd Land Sector and links to inter-decadal atmosphere-ocean variability
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DOI：
10.5194/tc-12-2461-2018
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发表时间：
2018-07-26
期刊：
影响因子：
5.2
通讯作者：
Tett, Simon F. B.
中科院分区：
文献类型：
--
作者：
Christie, Frazer D. W.;Bingham, Robert G.;Tett, Simon F. B.
在过去的20年里，卫星遥感已经捕获了大量的冰川下降，这些冰川将南极西部冰盖排放到海洋中，特别是在阿蒙森海地区。沿着邻近的玛丽伯德地区，位于思韦茨冰川到罗斯冰架的西部，冰川变化只得到很少的监测。在这里，我们使用光学卫星图像跟踪2003年至2015年期间Marie Byrd Land Sector的地线迁移，并将观测到的变化与ICESat和cryosat -2衍生的地表高程和厚度变化记录进行比较。在观测期间，33%的接地线后退，其余2200公里长的海岸线没有明显的前进记录。沿650公里长的盖兹冰架观察到最大的退缩率，再往西只发生了轻微的退缩。盖兹冰架以西的相对冰川学稳定性可归因于南极环极流在西经135度的大陆架断裂处的辐散，与大陆架形态的转变相一致。沿盖茨冰架，在CryoSat-2时代，与早期观测相比，接地线退缩减少了68%。气候再分析数据表明，在这一后期，由风驱动的环极深水上升流可能已经减少，这表明观测到的减缓是对海洋强迫减少的响应。然而，由于缺乏盖茨冰架接地带附近全面的海洋学和测深信息，很难评估内在冰川动力学的作用，或者更复杂的冰盖-海洋相互作用，以缓和这种减缓。总的来说，我们的发现强调了大气和海洋相互作用的空间和年代际变率在减缓南极洲周围冰川变化中的重要性。
Over the past 20 years satellite remote sensing has captured significant downwasting of glaciers that drain the West Antarctic Ice Sheet into the ocean, particularly across the Amundsen Sea Sector. Along the neighbouring Marie Byrd Land Sector, situated west of Thwaites Glacier to Ross Ice Shelf, glaciological change has been only sparsely monitored. Here, we use optical satellite imagery to track grounding-line migration along the Marie Byrd Land Sector between 2003 and 2015, and compare observed changes with ICESat and CryoSat-2-derived surface elevation and thickness change records. During the observational period, 33% of the grounding line underwent retreat, with no significant advance recorded over the remainder of the similar to 2200 km long coastline. The greatest retreat rates were observed along the 650 km-long Getz Ice Shelf, further west of which only minor retreat occurred. The relative glaciological stability west of Getz Ice Shelf can be attributed to a divergence of the Antarctic Circumpolar Current from the continental-shelf break at 135 degrees W, coincident with a transition in the morphology of the continental shelf. Along Getz Ice Shelf, grounding-line retreat reduced by 68% during the CryoSat-2 era relative to earlier observations. Climate reanalysis data imply that wind-driven upwelling of Circumpolar Deep Water would have been reduced during this later period, suggesting that the observed slowdown was a response to reduced oceanic forcing. However, lack of comprehensive oceanographic and bathymetric information proximal to Getz Ice Shelf's grounding zone make it difficult to assess the role of intrinsic glacier dynamics, or more complex ice-sheet-ocean interactions, in moderating this slowdown. Collectively, our findings underscore the importance of spatial and inter-decadal variability in atmosphere and ocean interactions in moderating glaciological change around Antarctica.